The number of days lost to sickness absence has fallen by 47 million over the past 20 years, according to official figures.

The total has been cut from 178 million in 1993 to 131 million last year, an average of just over four days a year per worker.

The percentage of hours lost to sickness in private firms was 1.8%, compared with 2.9% in the public sector, said the Office for National Statistics (ONS).

Workers in London had the lowest percentage of hours lost to sickness, at 1.5%, while the highest were in the East Midlands, Wales and the North East at 2.4%.

The main cause for working days lost last year was musculoskeletal conditions such as back and neck pain, leading to 31 million days lost, followed by minor illnesses such as coughs and colds (27 million).

Around 15 million days were lost because of stress, anxiety or depression, up from 11.8 million in 2010.

Men generally have lower sickness absence rates than women, although the new figures show falls among all workers and all age groups since 1993.

Sickness absence increases with age but falls after eligibility for the state pension.

ONS statistician Jamie Jenkins said: "On average workers had 4.4 days off due to sickness absence in 2013, down from 7.2 days in 1993.

"Sickness has generally been falling over the 20-year period, but since 2011 the fall appears to have levelled off with very little change over the past two years."

Dr John Philpott, director of The Jobs Economist, said: "Although the overall rate of sickness absence from work is on a broadly downward trend, more working days are being lost to the common mental health problems of stress, depression and anxiety, which accounted for 15.2 million lost working days in 2013, up from 11.8 million days lost in 2010.

"Given the possibility that people may cite other reasons for absence due to mental health issues because of the social stigma attached to such conditions, the underlying problem is likely to be even worse.

"Moreover, sickness absence statistics don't detect people suffering from common mental health problems who soldier on at work for fear that highlighting a condition might put their job at risk."

Managers, directors and senior officials take fewer days off sick, while the self-employed are less likely to have a spell of sickness, said the ONS report.

In the public sector, sickness rates are highest for those working in the health service, where around 3.4% of hours were lost to sickness last year, compared with 3% in central government and 2.7% in local government.

TUC general secretary Frances O'Grady said: "These figures prove that there is no such thing as a sickie culture, with the number of days lost to ill-health falling as employers get better at managing sickness absence.

"The real health threat we face is the growing culture of presenteeism, where unwell staff are pressured into coming to work by their bosses. This can prolong illness, spread diseases and cause stress throughout the workplace."